Worldwide, the quality of drinking water is monitored and regulatedon the basis of end product testing. Samples are collected routinely either from the outlet of the treatment works, or following distribution. These are then analyzed for a range of physical, chemical, and microbiological parameters. Compliance with regulatory water quality standards is determined on the basis of these results. The indicator concept on which current regulatory microbiological standards is predicted dates back over 100 years. The continuing burden of waterborne infectious intestinal illness and the recognition of chlorine resistant pathogens such as Cryptosporidium and enteric viruses has led to a realization that a new approach to assuring microbiological drinking water quality is required. Hazard Analysis Critical Control Point (HACCP), a quality assurance system developed as a means of ensuring food safety, provides a paradigm for assuring the microbiological safety of drinking water. Water is considered as a food in many instances and there are obvious parallels between the production of foods and drinking water. The principles of HACCP are derived from Failure Mode and Effect Analysis, an engineering system that is well known to chemical engineers and which has been used in the design and evaluation of water treatment processes. The HACCP principle can be applied to the productionand distribution of drinking water. By instigating a HACCP system, control is transferred from solely end product testing, to the design of treatment processes and production of drinking water. Includes 18 references, tables, figures.